Speed change gear

ABSTRACT

Speed change gears of the planetary gear type suited for applications within fluid couplings used upon automotive vehicles includes an input shaft, a first clutch for releasing or coupling a second ring gear and a third sun gear simultaneously from or to the input shaft, a second clutch for releasing or coupling a first sun gear and a second sun gear simultaneously from or to the input shaft, a first planetary gear engaged with the first sun gear, a first ring gear engaging the first planetary gear, a first carrier rotatably supporting the first planetary gear, a second planetary gear engaged with the second sun gear and the second ring gear, a second carrier rotatably supporting the second planetary gear, a third planetary gear enmeshed with the third sun gear, a third ring gear interengaged with the third planetary gear and coupled to the first ring gear, a third carrier rotatably supporting the third planetary gear and coupled to the second carrier and to an output shaft, a first brake capable of locking the first sun gear and the second sun gear simultaneously to a casing, a second brake capable of locking the first carrier relative to the casing, and a third brake capable of locking the first ring gear and the third gear simultaneously to the casing.

This is a division, of application Ser. No. 440,545, filed Feb. 7, 1974now U.S. Pat. No. 3,946,622.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to speed change gears and moreparticularly to speed change gears suited for applications with fluidcouplings or torque converters used upon vehicles, especiallyautomobiles.

2. Description of the Prior Art

It is desirable that the gear type speed changer of automatictransmissions used upon large automotive vehicles, such as for example,trucks and buses should be capable of shifting between at least fourforward speeds and operating with one reverse speed. This speed changingmechanism may be realized by suitably combining three, four or even moresimple sets of planetary gears of the single pinion or the double piniontype, of which a variety of combinations may be considered. Within anycombination of such planetary gear sets, the following conditions aredesired to be satisfied:

(1) The output shaft should be coupled to the same elements within eachspeed range.

(2) In order to reduce the circumferential speed of the bearing of eachelement of the planetary gear set, the number of its revolutions shouldbe small.

(3) The tooth load, that is, the tangential force, of each elementshould be small so as to maintain the strength of the gear teeth.

(4) The gear set should meet the meshing conditions for the number ofteeth. The sun gear whose diameter is minimized, as well as eachplanetary pinion gear, should have the necessary number of teeth.

(5) Within each planetary gear set, the coupling relationship among theelements should be simple and the distance from each other be short.

(6) When attaining speed shifts by frictional coupling means duringforward drive, such speed shifts should be available through onecoupling means alone.

Conventional apparatus failed to efficiently attain these conditions.

SUMMARY OF THE INVENTION

Accordingly, the principal object of the present invention is theprovision of an efficient speed change gear mechanism of the planetarygear type which is able to provide at least four forward speeds and onereverse speed.

The foregoing object and other objectives are achieved according to thisinvention through the provision of a speed change gear mechanismemploying three simple planetary gear sets of the single pinion type,two clutch units, and three brake units. The movable members of thethree planetary gear sets are suitably coupled to each other, and theclutch units and brake units are suitably coupled, uncoupled, locked andunlocked.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other objects, features and attendant advantages of the presentinvention will be more fully appreciated as the same becomes betterunderstood from the following detailed description when considered inconnection with the accompanying drawings, in which like referencecharacters designate like or corresponding parts throughout the severalviews, and wherein:

FIG. 1 is a view schematically illustrating a first embodiment of aspeed change gear constructed according to the present invention andshowing its cooperative parts;

FIG. 2 is a view similar to that of FIG. 1 illustrating however a secondembodiment of the present invention;

FIG. 3 is a view similar to that of FIG. 1 illustrating however a thirdembodiment of the invention;

FIG. 4 is a view similar to that of FIG. 1 illustrating however, afourth embodiment of the present invention;

FIG. 5 is a view similar to that of FIG. 1 illustrating however a fifthembodiment of the present invention;

FIG. 6 is a view similar to that of FIG. 1 illustrating however a sixthembodiment of the present invention;

FIG. 7 is a view similar to that of FIG. 1 illustrating however aseventh embodiment of the present invention;

FIG. 8 is a view similar to that of FIG. 1 illustrating however aneighth embodiment of the present invention; and

FIG. 9 is a view similar to that of FIG. 1 illustrating however a ninthembodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and more particularly to FIG. 1 thereof,there is schematically shown a first embodiment of the present inventionwherein a generally known three-element one-stage two-phase torqueconverter, generally indicated by the reference character 10 includes apump impeller 11 connected to an input shaft 1, a turbine runner 12connected to a first intermediate shaft 2, and a stator wheel 13supported by means of a casing 100 through means of a one-way brake 101.A first clutch 21 is interposed between the first intermediate shaft 2and a second intermediate shaft 3 disposed serially and coaxially withthe first intermediate shaft 2, the first clutch 21 of course serving tocouple the intermediate shafts together or uncouple them from eachother, and a hollow, third intermediate shaft 5 is also disposed uponthe second intermediate shaft 3 in coaxial fashion.

A first sun gear 41 and a second sun gear 51 of a first planetary gearset, generally indicated by the reference character 40, and of a secondplanetary gear set, generally indicated by the reference character 50,respectively, are secured upon the third intermediate shaft 5 by splinemeans or the like so as to allow the sun gears 41 and 51 to rotate withthe third intermediate shaft 5. A second clutch 22 is similarlyinterposed between the third intermediate shaft 5 and the firstintermediate shaft 2 so as to couple these shafts together or uncouplethem from each other. Furthermore, a first brake 31 is interposedbetween the third intermediate shaft 5 and the casing 100, and when thisbrake is actuated, the third intermediate shaft 5 as well as the firstand second sun gears 41 and 51 are locked relative to casing 100.

The first planetary gear set 40 is seen to comprise the first sun gear41, a first planetary gear 42 engaged with the first sun gear 41, afirst ring gear 43 enmeshed with the first planetary gear 42, and afirst carrier 44 rotatably supporting the first planetary gear 42. Asecond brake 32 is interposed between the first carrier 44 and thecasing 100, and when this brake is actuated, the first carrier 44 islocked relative to casing 100.

The second planetary gear set 50 similarly comprises the second sun gear51, a second planetary gear 52 interengaged with the second sun gear 51,a second ring gear 53 engaged with the second planetary gear 52, anddrivingly coupled to the second intermediate shaft 3, and a secondcarrier 54 rotatably supporting the second planetary gear 52.

A third sun gear 61 of a third planetary gear set, generally indicatedby the reference character 60, is also secured upon the secondintermediate shaft 3 by spline means or the like whereby the sun gear 61is able to rotate with the second intermediate shaft 3, and the thirdplanetary gear set 60 further comprises a third planetary gear 62engaged with the third sun gear 61, a third ring gear 63 interengagedwith the third planetary gear 62 and drivingly coupled to the first ringgear 43, and a third carrier 64 rotatably supporting the third planetarygear 62 and drivingly coupled to the second carrier 54 as well as to anoutput shaft 4 coaxially and serially disposed with respect to thesecond intermediate shaft 3. A third brake 33 is interposed between thecasing 100 and the two ring gears 43 and 63 and when this brake isactuated, the ring gears 43 and 63 are locked relative to casing 100.

Within each of the simple, single pinion type planetary gear sets, thefollowing conditions prevail:

    N.sub.Rn -(1+I.sub.n)X.sub.Cn = 0

(n + 1, 2, 3, . . . )

wherein:

N_(Rn) = the number of revolutions of the ring gear

N_(Cn) = the number of revolutions of the carrier

N_(Sn) = the number of revolutions of the sun gear

I_(n) = the radial ratio between the ring gear and the sun gear

More specifically, the radial ratios within the speed change gearmechanism of the present invention are, for example, I₁ = 0.28, I₂ =0.52 and I₃ = 0.36. The following table summarizes the gear ratios inconnection with the operation of clutches 21 and 22, and brakes 31, 32and 33:

    ______________________________________                                        Speed Ranges                                                                             21     22     31   32   33   Gear Ratios                           ______________________________________                                        first speed                                                                              0                       0    1 : 3.778                             second speed                                                                             0                  0         1 : 2.425                             third speed                                                                              0             0              1 : 1.520                             fourth speed                                                                             0      0                     1 : 1.000                             reverse 1st speed 0                     1 :-4.342                             reverse 2nd speed 0                     1 :-1.741                             ______________________________________                                    

As described above, the present invention thus makes it feasible torealize gear ratios for four forward speeds and two reverse speeds bythe utilization of three simple planetary gear sets of the single piniontype and according to a further aspect of the present invention,friction wheels may readily be used in place of the noted gears in orderto constitute the foregoing speed change mechanism.

Table 1 shows the relationship between the number of revolutions and thetangential force of each of the elements of the planetary gear setswithin the individual speed ranges, the ratio of the number ofrevolutions being based upon the assumption that the number ofrevolutions of the input shaft is 1, and the tangential force upon theassumption that the input shaft torque exerted upon the ring gear is 1,and these assumptions apply throughout the other embodiments hereinafterdescribed. Within the Tables, the symbols utilized have the followingdesignations:

A = the speed ranges

B = the planetary gear sets

N = the number of revolutions

W = the tangential force

X_(n) = the n-th planetary gear set

S_(n) = the n-th sun gear

P_(n) = the n-th planetary gear

RG_(n) = the n-th ring gear

Cn = the n-th carrier

                                      TABLE 1                                     __________________________________________________________________________    B     X1              X2              X3                                      A     S1  C1  RG1 P1  S2  C2  RG2 P2  S3  C2  RG3 P3                          __________________________________________________________________________       N  -1.5                                                                              -0.25                                                                             0.0 0.70                                                                              -1.15                                                                             0.26                                                                              1.00                                                                              3.06                                                                              1.00                                                                              0.26                                                                              0.0 -0.33                       F1 W  0.0 0.0 0.0 0.0 0.0 0.00                                                                              0.00                                                                              0.00                                                                              2.78                                                                              5.56                                                                              2.78                                                                              2.78                           N  -0.72                                                                             -0.00                                                                             0.20                                                                              0.56                                                                              -0.72                                                                             0.41                                                                              1.00                                                                              2.45                                                                              1.00                                                                              0.41                                                                              0.28                                                                              -0.66                       F2 W  1.11                                                                              2.23                                                                              1.11                                                                              1.11                                                                              0.60                                                                              1.20                                                                              0.62                                                                              0.60                                                                              1.11                                                                              2.23                                                                              1.11                                                                              1.11                           N  0.0 0.42                                                                              0.53                                                                              0.32                                                                              0.0 0.66                                                                              1.00                                                                              1.43                                                                              1.00                                                                              0.66                                                                              0.53                                                                              -0.38                       F3 W  0.0 0.0 0.0 0.0 1.00                                                                              2.00                                                                              1.00                                                                              1.00                                                                              0.00                                                                              0.0 0.0 0.0                            N  1.00                                                                              0.22                                                                              0.0 -0.61                                                                             1.00                                                                              -0.23                                                                             -0.87                                                                             -2.67                                                                             -0.87                                                                             -0.23                                                                             0.00                                                                              0.72                        R1 W  0.0 0.0 0.0 0.0 1.92                                                                              3.85                                                                              1.92                                                                              1.92                                                                              5.34                                                                              10.68                                                                             5.34                                                                              5.34                           N  1.00                                                                              0.00                                                                              -0.28                                                                             -0.73                                                                             1.00                                                                              -0.57                                                                             -1.39                                                                             -3.41                                                                             -1.39                                                                             -0.57                                                                             -0.28                                                                             0.02                        R2 W  2.14                                                                              4.23                                                                              2.14                                                                              2.14                                                                              0.77                                                                              1.54                                                                              0.77                                                                              0.77                                                                              2.14                                                                              4.23                                                                              2.14                                                                              2.14                        __________________________________________________________________________

Because the gear ratio at the fourth forward speed is 1:1.00, 15 thenumber of revolutions of each planetary gear is 0.00 when the number ofrevolutions of each sun gear, ring gear and carrier is 1.00. Thetangential force is much smaller within the fourth forward speed rangethan in the other speed ranges due to the fact that within the fourthforward speed range, the torque of the input shaft is distributed to theindividual elements through the coupling of at least two clutches, whilein the other speed ranges, the torque of the input shaft is imparted tothe individual elements through coupling of only one of the clutches.Hence, for the fourth speed range wherein the gear ratio is 1.00, thenumber of revolutions and the tangential force are not shown in Table 1.Similar conditions prevail for the other embodiments of the presentinvention as will be described hereinafter.

Referring now to FIG. 2, there is schematically shown a secondembodiment of the present invention which is similar to the firstembodiment and wherein there is further included a fourth sun gear 71aof a fourth planetary gear set, generally indicated by the referencecharacter 70a, of the single pinion type, secured upon the outut shaft 4by spline means or the like whereby the sun gear is able to rotate withthe output shaft 4. The fourth planetary gear set 70a further includes afourth planetary gear 72a engaged with the sun gear 71a, a fourth ringgear 73a interengaged with the fourth planetary gear 72a and integrallycoupled to the third ring gear 63 and a fourth carrier 74a rotatablysupporting the fourth planetary gear 72a. Since ring gear 73a is coupledto ring gear 63a, gear 73a is locked relative to casing 30 when thethird brake 33 is actuated. A fourth brake 34a is similarly interposedbetween the fourth carrier 74a and the casing 30, and when this brake isactuated, the fourth carrier 74a is locked relative thereto.

Within this embodiment, the radial ratios are: I₁ = 0.280, I₂ = 0.520,I₃ = 0.360, and I₄ = 0.562, and the gear ratios within the individualspeed ranges, five forward speed ranges and three reverse speed rangesin connection with the operations of clutches 21 and 22 and brakes 31,32, 33 and 34a are summarized in the following table:

    ______________________________________                                        Speed Ranges                                                                             21     22     31  32  33  34a  Gear Ratios                         ______________________________________                                        first speed                                                                              0                         0    1 : 5.34                            second speed                                                                             0                     0        1 : 3.78                            third speed                                                                              0                 0            1 : 2.48                            fourth speed                                                                             0             0                1 : 1.52                            fifth speed                                                                              0      0                       1 : 1.00                            reverse 1st speed 0                  0    1 :-7.34                            reverse 2nd speed 0              0        1 :-4.34                            reverse 3rd speed 0          0            1 :-1.74                            ______________________________________                                    

Table 2 shows the relationship between the number of revolutions and thetangential force of each of the elements of the planetary gear setswithin each speed range.

Referring now to FIG. 3, there is schematically shown a third embodimentof the present invention which is also similar to the first embodimentand wherein there is included a hollow third intermediate shaft 6bcoaxially disposed upon the output shaft 4, and a fourth sun gear 71b ofa fourth planetary gear set generally indicated by the referencecharacter 70b, of the single pinion type, is secured upon the thirdintermediate shaft 6b by spline means or the like whereby the sun gear71b is able to rotate with the third intermediate shaft 6b. The fourthplanetary gear set 70b further has a fourth planetary gear 72b engagedwith the fourth sun gear 71b, a fourth ring gear 73b enmeshed with thefourth planetary gear 72b and integrally coupled to the output shaft 4,and a fourth carrier 74b rotatably supporting the fourth planetary gear72b. The third intermediate shaft 6b is integrally coupled to the thirdring gear 63 and consequently, this intermediate shaft is lockedrelative to casing 30 when the third brake 33 is actuated. A fourthbrake 34b is similarly installed between the fourth carrier 74b and thecasing 30 and when this brake is actuated, the fourth carrier 74b islocked relative to casing 30.

    TABLE 2      B X1 X2 X3 X4 A S1 C1 RG1 P1 S2 C2 RG2 P2 S3 C2 RG3 P3 S4 C4 RG4     P4        N -1.33 -0.39 -0.11 0.77-1.38 0.19 1.00 3.39 1.00 0.19 -0.11     -0.91 0.19 0.00 -0.11 -0.48 F1 W 0.0 0.0 0.0 0.0 0.0 0.00 0.00 0.00 2.78     5.56 2.78 2.78 2.78 5.56 2.78 2.78  N -1.15 -0.25 0.0 0.70 -1.15 0.26     1.00 3.06 1.00 0.26 0.0 -0.83 0.26 0.10 0.0 -0.43 F2 W 0.0 0.0 0.0 0.0     0.0 0.00 0.00 0.00 2.78 5.56 2.78 2.79 0.0 0.0 0.0 0.0  N -0.72 -0.00     0.20 0.56 0.72 0.41 1.00 2.45 1.00 0.41 0.20 -0.66 0.41 0.28 0.20 -0.35     F3 W 1.11 2.23 1.11 1.11 0.60 1.20 0.60 0.60 1.11 2.23 1.11 1.11 0.0 0.0     0.0 0.0  N 0.0 0.42 0.53 0.32 0.0 0.66 1.00 1.43 1.00 0.66 0.53 -0.330.66      0.58 0.53 -0.20 F4 W 0.0 0.0 0.0 0.0 1.00 2.00 1.00 1.00 0.00 0.0 0.0     0.0 0.0 0.0 0.0 0.0  N 1.00 0.28 0.08 -0.56 1.00 -0.14 -0.73 -2.46 -0.73     -0.14 0.08 0.66 -0.14 0.0 0.08 0.35 R1 W 0.0 0.0 0.0 0.0 1.92 3.85 1.92     1.92 5.34 10.68 5.34 5.34 5.34 10.68 5.34 5.34  N 1.00 0.22 0.0 -0.61     1.00 -0.23 -0.87 -2.67 -0.87 -0.23 0.0 0.72 -0.23 -0.08 0.0 0.38 R2 W     0.0 0.0 0.0 0.0 1.92 3.85 1.92 1.92 5.34 10.68 5.34 5.34 0.0 0.0 0.0 0.0      N 1.00 0.00 -0.28 -0.78 1.00 -0.57 -1.39 -3.41 -1.39 -0.57 -0.28 0.92     -0.57 -0.39 -0.28 0.48 R3 W 2.14 4.28 2.14 2.14 0.77 1.54 0.77 0.77 2.14     4.23 2.14 2.14 0.00.0 0.0 0.0

In this embodiment, the radial ratios are: I₁ = 0.280, I₂ = 0.520, I₃ =0.360 and I₄ = 0.562 and the gear ratios within the individual speedranges, five forward speed ranges and three reverse speed ranges, inconnection with the operations of clutches 21 and 22, and brakes 31, 32,33 and 34b are summarized in the following table:

    ______________________________________                                        Speed Ranges                                                                             21     22     31  32  33  34b  Gear Ratios                         ______________________________________                                        first speed                                                                              0                         0    1 : 8.72                            second speed                                                                             0                     0        1 : 3.78                            third speed                                                                              0                 0            1 : 2.43                            fourth speed                                                                             0             0                1 : 1.52                            fifth speed                                                                              0      0                       1 : 1.00                            reverse 1st speed 0                  0    1 :-13.85                           reverse 2nd speed 0              0        1 :-4.34                            reverse 3rd speed 0          0            1 :-1.74                            ______________________________________                                    

Table 3 also shows the relationship between the number of revolutionsand the tangential force of each of the elements of the planetary gearsets within each speed range.

Turning now to FIG. 4, a fourth embodiment of the present invention isseen to be quite similar to the first embodiment, although

    TABLE 3      B X1 X2 X3 X4 A S1 C1 RG1 P1 S2 C2 RG2 P2 S3 C2 RG3 P3 S4 C4 RG4     P4        N -1.59 -0.51 -0.20 0.84-1.59 0.11 1.00 3.69 1.00 0.11 -0.20     -1.00 -0.20 -0.08 0.11 4.52 F1 W 0.0 0.0 0.0 0.0 0.0 0.0 0.00 0.00 2.78     5.56 2.78 2.78 4.94 9.39 4.94 4.94  N -1.15 -0.25 0.0 0.70 -1.15 0.20     1.00 3.06 1.00 0.26 0.0 -0.83 0.0 0.17 0.26 0.43 F2 W 0.0 0.0 0.0 0.0     0.0 0.00 0.00 0.00 2.78 5.56 2.78 2.78 0.0 0.0 0.0 0.0  N -0.72 -0.00     0.20 0.56 -0.72 0.41 1.08 2.45 1.00 0.41 0.20 -0.66 1.20 0.34 0.41 0.35     F3 W 1.11 2.23 1.11 1.11 0.60 1.20 0.60 0.60 1.11 2.23 1.11 1.11 0.0 0.0     0.0 0.0  N 0.0 0.42 0.53 0.32 0.0 0.66 1.00 1.43 1.00 0.66 0.53 -0.380.53      0.61 0.66 0.23 F4 W 0.0 0.0 0.0 0.0 1.00 2.00 1.00 1.00 0.00 0.0 0.0     0.0 0.0 0.0 0.0 0.0  N 1.00 0.32 0.13 -0.53 1.00 -0.87 -0.63 -2.32 -0.63     -0.87 0.13 0.63 0.13 0.00 -0.87 -0.33 R1 W 0.0 0.0 0.0 0.0 1.92 3.05     1.92 5.34 10.68 5.34 5.34 9.51 19.01 9.51 9.51  N 1.00 0.22 0.0 -0.61     1.00 -0.23 -0.37 -2.67 -0.8 -0.233 0.0 0.72 0.0 -0.15 -0.23 -0.33 R2 W     0.0 0.0 0.0 0.0 1.92 3.35 1.92 1.92 5.34 10.68 5.34 5.34 0.0 0.0 0.0 0.0      N 1.00 0.00 -0.23 -0.78 1.00 -0.57 -1.39 -3.41 -1.39 -0.57 -0.28 0.92     -0.28 -0.47 -0.57 -0.48 R3 W 2.14 4.23 2.14 2.14 0.77 1.54 0.77 0.77     2.14 4.28 2.14 2.140.0 0.0 0.0 0.0

the present embodiment includes a hollow third intermediate shaft 6cdisposed coaxially upon the output shaft 4 and a fourth sun gear 71c ofa fourth planetary gear set, generally indicated by the referencecharacter 70c, of the single pinion type, is secured upon the thirdintermediate shaft 6c by spline means or the like so as to allow sungear 71c to rotate with the third intermediate shaft 6c. The fourthplanetary gear set 70c further includes a fourth planetary gear 72cengaged with the fourth sun gear 71c, a fourth ring gear 73cinterengaged with the fourth planetary gear 72c and coupled to the thirdcarrier 64, and a fourth carrier 74c rotatably supporting the fourthplanetary gear 72c and the fourth carrier integrally coupled to thethird ring gear 63 so as to be locked when the third brake 33 isactuated. A fourth brake 34c is similarly installed between the thirdintermediate shaft 6c and the casing 30 and consequently, when thefourth brake 34 c is actuated, the third intermediate shaft 6c is lockedrelative thereto.

Concrete examples of the radial ratios within this embodiment are: I₁ =0.280, I₂ = 0.520, I₃ = 0.360 and I₄ = 0.562. The gear ratios within theindividual speed ranges, five forward speed ranges and three reversespeed ranges, in connection with the operation of clutches 21 and 22,and brakes 31, 32, 33 and 34c are tabulated below:

    ______________________________________                                        Speed Ranges                                                                             21     22     31  32  33  34c  Gear Ratios                         ______________________________________                                        first speed                                                                              0                     0        1 : 3.78                            second speed                                                                             0                 0            1 : 2.43                            third speed                                                                              0                         0    1 : 2.00                            fourth speed                                                                             0             0                1 : 1.52                            fifth speed                                                                              0      0                       1 : 1.00                            reverse 1st speed 0              0        1 :-4.34                            reverse 2nd speed 0          0            1 :-1.74                            reverse 3rd speed 0                  0    1 :-0.92                            ______________________________________                                    

Table 4 shows the relationship between the number of revolutions and thetangential force of each of the elements of the planetary gear setswithin each speed range.

Reference now being made to FIG. 5, a fifth embodiment of the presentinvention is shown wherein the system is similar to that of the firstembodiment and additionally includes a fourth sun gear 71d, of a fourthplanetary gear set, generally indicated by the reference character 70d,of the single pinion type, secured upon the output shaft 4 whereby sungear 71d can rotate therewith, and wherein further the fourth planetarygear set 70d also includes a fourth planetary gear 72d engaged with thefourth sun gear 71d, a fourth ring gear 73d enmeshed

    TABLE 4      B X1 X2 X3 X4 A S1 C1 RG1 P1 S2 C2 RG2 P2 S3 C2 RG3 P3 S4 C4 RG4     P4        N -1.15 -0.25 0.0 0.70-1.15 0.26 1.00 3.06 1.00 0.26 0.0 -0.83     -2.36 0.26 1.00 2.04 F1 W 0.0 0.0 0.0 0.0 0.0 0.0 0.00 0.00 2.78 5.56     2.78 2.78 0.0 0.00 0.00 0.00  N -0.72 -0.00 0.20 0.56 -0.72 0.41 1.00     2.45 1.00 0.41 0.20 -0.66 -1.69 0.41 1.00 1.63 F2 W 1.11 2.23 1.11 1.11     0.60 1.20 0.60 0.60 1.11 2.23 1.11 1.11 0.0 0.00 0.00 0.00  N 0.0 0.42     0.53 0.32 0.0 0.66 1.00 1.43 1.00 0.66 0.53 -0.38 -0.56 0.66 1.00 0.95     F3 W 0.0 0.0 0.0 0.0 1.00 2.00 1.00 1.00 0.00 0.0 0.0 0.0 0.0 0.00 0.00     0.00  N 0.36 0.63 0.70 0.21 0.36 0.78 1.00 0.91 1.00 0.78 0.70 -0.29 0.0     0.78 1.00 0.61 F4 W 0.0 0.0 0.0 0.0 0.0 0.00 0.00 0.00 0.00 0.0 0.0 0.0     1.00 2.00 1.00 1.00  N 1.00 1.74 1.95 0.58 1.00 2.17 2.77 2.53 2.77 2.17     1.95 -0.68 0.0 2.17 2.77 1.69 F6 W 0.0 0.0 0.0 0.0 1.92 3.85 1.92 1.92     0.0 0.0 0.0 0.0 1.92 3.85 1.92 1.92  N 1.00 0.22 0.0 -0.61 1.00 -0.23     -0.87 -2.67 -0.87 -0.23 0.0 0.72 2.05 -0.23 -0.87 -1.78 R1 W 0.0 0.0 0.0     0.0 1.92 3.85 1.92 1.92 5.34 10.68 5.34 5.34 0.0 0.00 0.00 0.00  N 1.00     0.00 -0.28 -0.78 1.00 -0.57 -1.39 -3.41 -1.39 -0.57 -0.28 0.92 2.35     -0.57 -1.39 -2.27 R2 W 2.14 4.28 2.14 2.14 0.77 1.54 0.77 0.77 2.14 4.28     2.14 2.140.0 0.00 0.00 0.00

with the fourth planetary gear 72d, and a fourth carrier 74d rotatablysupporting the fourth planetary gear 72d and being integrally coupled tothe third ring gear 63 whereupon such carrier is locked relative tocasing 20 when the third brake 33 is actuated. A fourth brake 34d isalso provided in conjunction with the fourth ring gear 73d whereuponsuch brake being actuated, the fourth ring gear 73d will be lockedrelative to casing 30.

Concrete examples of the radial ratios in this embodiment are: I₁ =0.280, I₂ = 0.520, I₃ = 0.360 and I₄ = 0.562 and the following tablesummarizes the gear ratios within the individual speed ranges, fiveforward speed ranges and three reverse speed ranges in connection withthe operations of clutches 21 and 22 and brakes 31, 32, 33 and 34d:

    ______________________________________                                        Speed Ranges                                                                             21     22     31  32  33  34d  Gear Ratios                         ______________________________________                                        first speed                                                                              0                     0        1 : 3.78                            second speed                                                                             0                         0    1 : 2.78                            third speed                                                                              0                 0            1 : 2.43                            fourth speed                                                                             0             0                1 : 1.52                            fifth speed                                                                              0      0                       1 : 1.00                            reverse 1st speed 0              0        1 :-4.34                            reverse 2nd speed 0                  0    1 :-2.42                            reverse 3rd speed 0          0            1 :-1.74                            ______________________________________                                    

Table 5 shows the relationship regarding the number of revolutions andthe tangential force of each of the elements of the planetary gear setswithin each speed range.

Referring now to FIG. 6, there is schematically shown a sixth embodimentof the present invention, which is also similar to the first embodiment,the present embodiment including a hollow third intermediate shaft 6ecoaxially disposed upon the output shaft 4, and a fourth sun gear 71e,of a fourth planetary gear set, generally indicated by the referencecharacter 70e, of the single pinion type, secured upon the thirdintermediate shaft 6e by spline means or the like whereby such sun gearis permitted to rotate with the third intermediate shaft 6e. The fourthplanetary gear set 70e is further provided with a fourth planetary gear72e engaged with the fourth sun gear 71e, a fourth ring gear 73einterengaged with the fourth planetary gear 72e, and a fourth carrier74e rotatably supporting the fourth planetary gear 72e and beingintegrally coupled to the output shaft 4. The third intermediate shaft6e is integrally coupled to the third ring gear 63 whereby theintermediate shaft 6e is able to be locked relative to casing 30 whenthe third brake 33 is actuated. A fourth brake 34e is similarly providedbetween the fourth ring gear 73e and the casing 30 and when this brake34e is actuated, a fourth ring gear 73e is also locked relative tocasing 30.

    TABLE 5      B X1 X2 X3 X4 A S1 C1 RG1 P1 S2 C2 RG2 P2 S3 C2 RG3 P3 S4 C4 RG4     P4        N -1.15 -0.25 0.0 0.70-1.15 0.26 1.00 3.06 1.00 0.26 0.0 -0.83 0     .26 0.00 -0.15 -0.63 F1 W 0.0 0.0 0.0 0.0 0.0 0.00 0.00 0.00 2.78 5.56     2.78 2.78 0.0 0.0 0.0 0.0  N -0.87 -0.09 0.13 0.61 -0.87 0.36 1.00 2.67     1.00 0.36 0.13 -0.72 0.36 0.13 0.0 -0.59 F2 W 0.0 0.0 0.0 0.0 0.0 0.00     0.00 0.00 2.78 5.56 2.78 2.78 1.73 3.56 1.73 1.73  N -0.72 -0.00 0.28     0.56 -0.72 0.41 1.00 2.45 1.00 0.41 0.28 -0.66 0.41 0.28 0.08 -0.54 F3 W     1.11 2.23 1.11 1.11 0.60 1.20 0.60 0.60 1.11 2.23 1.11 1.11 0.0 0.0 0.0     0.0  N 0.0 0.42 0.53 0.32 0.0 0.66 1.00 1.43 1.00 0.66 0.53 -0.380.66     0.53 0.47 -0.32 F4 W 0.0 0.0 0.0 0.0 1.00 2.00 1.00 1.00 0.00 0.0 0.0     0.0 0.0 0.0 0.0 0.0  N 1.00 0.22 0.0 -0.61 1.00 -0.23 -0.87 -2.67 -0.87     -0.23 0.0 0.72 -1.23 -0.00 0.13 0.50 R1 W 0.0 0.0 0.0 0.0 1.92 3.85 1.92     1.92 5.34 10.68 5.34 5.34 0.0 0.0 0.0 0.0  N 1.00 0.10 -0.15 -0.70 1.00     -0.41 -1.15 -3.06 -1.15 0.33 -0.41 -0.15 0.0 0.63 R2 W 0.0 0.0 0.0 0.0     1.92 3.85 1.92 1.92 5.34 10.68 5.34 5.34 3.42 6.84 3.42 3.42  N 1.00     0.00 -0.28 -0.78 1.00 -0.57 -1.39 -3.41 -1.39 -0.57 -0.23 0.92 -0.57     -0.28 -0.11 0.76 R3 W 2.14 4.28 2.14 2.14 0.77 1.54 0.77 0.77 2.14 4.28     2.14 2.140.0 0.0 0.0 0.0

The radial ratios within this embodiment are: I₁ = 0.280, I₂ = 0.520, I₃= 0.360 and I₄ = 0.437, and tabulated below are the gear ratios withinthe individual speed ranges, five forward speed ranges and three reversespeed ranges, in connection with the operations of clutches 21 and 22and brakes 31, 32, 33 and 34e:

    ______________________________________                                        Speed Ranges                                                                             21     22     31  32  33  34e  Gear Ratios                         ______________________________________                                        first speed                          0    1 : 13.22                           second speed                                                                             0                     0        1 : 3.78                            third speed                                                                              0                 0            1 : 2.43                            fourth speed                                                                             0             0                1 : 1.52                            fifth speed                                                                              0      0                       1 : 1.00                            reverse 1st speed                                                                        0                         0    1 : -5.36                           reverse 2nd speed 0              0        1 : -4.34                           reverse 3rd speed 0          0            1 : -1.74                           ______________________________________                                    

Table 6 shows the relationship between the number of revolutions and thetangential force of each of the elements of the planetary gear setswithin each speed range.

Turning now to FIG. 7, there is schematically shown a seventh embodimentof the present invention which is seen to be similar to the firstembodiment and also includes a hollow third intermediate shaft

    TABLE 6      B X1 X2 X3 X4 A S1 C1 RG1 P1 S2 C2 RG2 P2 S3 C2 RG3 P3 S4 C4 RG4     P4        N 1.00 0.41 0.25 -0.46 1.00 0.08 -0.41 -2.00 -0.41 0.08 0.25     0.54 0.25 0.08 0.0 -0.27 F1 W 0.0 0.0 0.0 0.0 1.92 3.85 1.92 1.92 5.34     10.68 5.34 5.34 12.22 24.45 12.22 12.22  N -1.15 -0.25 0.0 0.70 -1.15     0.26 1.00 3.06 1.00 0.26 0.0 -0.83 0.0 0.26 0.38 0.41 F2 W 0.0 0.0 0.0     0.0 0.0 0.00 0.00 0.00 2.78 5.56 2.78 2.78 0.0 0.0 0.0 0.0  N -0.72     -0.00 0.20 0.56 -0.72 0.41 1.00 2.45 1.00 0.41 0.20 -0.66 0.20 0.41 0.50     0.33 F3 W 1.11 2.23 1.11 1.11 0.60 1.20 0.60 0.60 1.11 2.23 1.11 1.11     0.0 0.0 0.0 0.0  N 0.0 0.42 0.53 0.32 0.0 0.66 1.00 1.43 1.00 0.66 0.53     -0.380.53 0.66 0.71 0.19 F4 W 0.0 0.0 0.0 0.0 1.00 2.00 1.00 1.00 0.00     0.0 0.0 0.0 0.0 0.0 0.0 0.0  N -2.47 -1.02 -0.61 1.13 -2.47 -0.19 1.00     4.94 1.00 -0.19 -0.61 -1.34 -0.61 -0.19 0.0 0.66 R1 W 0.0 0.0 0.0 0.0     0.0 0.0 0.0 0.0 2.78 5.56 2.78 2.78 6.36 12.71 6.36 6.36  N 1.00 0.22     0.0 -0.61 1.00 -0.23 -0.87 -2.67 -0.87 -0.23 0.0 0.72 0.0 -0.23 -0.38     -0.36 R2 W 0.0 0.0 0.0 0.0 1.02 3.00 1.92 1.92 5.34 10.68 5.34 5.34 0.0     0.0 0.0 0.0  N 1.00 0.00 -0.28 -0.78 1.00 -0.57 -1.39 -3.41 -1.39 -0.57     -0.28 0.92 -0.28 -0.57 -0.70 -0.46 R3 W 2.14 4.28 2.14 2.14 0.77 1.54     0.77 0.77 2.14 4.28 2.14 2.140.0 0.0 0.0 0.0

6f disposed coaxially upon the output shaft 4 and a fourth sun gear 71fof a fourth planetary gear set, generally indicated by the referencecharacter 70f, of the single pinion type, secured upon the thirdintermediate shaft 6f so as to rotate therewith. The fourth planetarygear set 70f comprises the fourth sun gear 71f, a fourth planetary gear72f engaged with the fourth sun gear 71f, a fourth ring gear 73fenmeshed with the fourth planetary gear 72f and drivingly coupled to thefirst intermediate shaft 3, and a fourth carrier 74f rotatablysupporting the fourth planetary gear 72f. A fourth brake 34f isinterposed between the third intermediate shaft 6f and the casing 30such that when this brake is actuated, the third intermediate shaft 6fis locked relative to casing 30, and the fourth carrier 74f isintegrally coupled to the third carrier 64 as well as the output shaft4.

The radial ratios within this embodiment are: I₁ = 0.280, I₂ = 0.520, I₃= 0.360 and I₄ = 0.280 and tabulated below are the gear ratios withinthe individual speed ranges, six forward speed ranges and two reversespeed ranges in connection with the operations of clutches 21 and 22 andbrakes 31, 32, 33 and 34f:

    ______________________________________                                        Speed Ranges                                                                             2l     22     31  32  33  34f  Gear Ratios                         ______________________________________                                        first speed                                                                              o                     o        1 : 3.78                            second speed                                                                             o                 o            1 : 2.43                            third speed                                                                              o             o                1 : 1.28                            fourth speed                                                                             o                         o    1 : 1.28                            fifth speed                                                                              o      o                       1 : 1.00                            sixth speed       o                  o    1 : 0.46                            reverse 1st speed o              o        1 : -4.34                           reverse 2nd speed o          o            1 : -1.74                           ______________________________________                                    

Table 7 shows the relationship between the number of revolutions and thetangential force of each of the elements of the planetary gear setswithin each speed range.

Referring now to FIG. 8, there is schematically shown an eighthembodiment of the present invention which is similar to the firstembodiment and further includes a fourth sun gear 71g, of a fourthplanetary gear set, generally indicated by the reference character 70g,of the single pinion type, fastened upon the first intermediate shaft 3at the rear end thereof and to the rear of the third planetary gear set60 by spline means or the like so that sun gear 71g is able to rotatewith the first intermediate shaft 3. The fourth planetary gear set 70gincludes

    TABLE 7      B X1 X2 X3 X4 A S1 C1 RG1 P1 S2 C2 RG2 P2 S3 C2 RG3 P3 S4 C4 RG4     P4        N 1.00 0.52 0.39 -0.37 1.00 0.25 -0.14 -1.63 -0.14 0.25 0.39     0.44 0.0 0.25 0.39 0.64 F1 W 0.0 0.0 0.0 0.0 1.92 3.85 1.92 1.92 5.34     10.68 5.34 5.34 5.34 10.68 5.34 5.34  N -1.15 -0.25 0.0 0.70 -1.15 0.26     1.00 3.06 1.00 0.26 0.0 -0.83 0.74 0.26 0.0 -1.21 F2 W 0.0 0.0 0.0 0.0     0.0 0.00 0.00 0.00 2.78 5.56 2.78 2.78 0.0 0.0 0.0 0.0  N -0.72 -0.00     0.20 0.56 -0.72 0.41 1.00 2.45 1.00 0.41 0.20 -0.66 0.70 0.41 0.28 -0.97     F3 W 1.11 2.23 1.11 1.11 0.60 1.20 0.60 0.60 1.11 2.23 1.11 1.11 0.0 0.0     0.0 0.0  N 0.0 0.42 0.53 0.32 0.0 0.66 1.00 1.43 1.00 0.66 0.53 -0.380.83      0.66 0.53 -0.56 F4 W 0.0 0.0 0.0 0.0 1.00 2.00 1.00 1.00 0.00 0.0 0.0     0.0 0.0 0.0 0.0 0.0  N 1.00 0.22 0.0 -0.61 1.00 -0.23 -0.87 -2.67 -0.87     -0.23 0.0 0.72 -0.64 -0.23 0.0 1.05 R1 W 0.0 0.0 0.0 0.0 1.92 3.85 1.92     1.92 5.34 10.68 5.34 5.34 0.0 0.0 0.0 0.0  N 1.00 0.00 -0.23 -0.78 1.00     -0.57 -1.39 -3.41 -1.39 -0.57 -0.23 0.92 -1.10 -0.57 -0.23 1.35 R2 W     2.14 4.28 2.14 2.14 0.77 1.54 0.77 0.77 2.14 4.28 2.14 2.14 0.0 0.0 0.0     0.0

the fourth sun gear 71g, a fourth planetary gear 72g engaged with thefourth sun gear 71g, a fourth ring gear 73g interengaged with the fourthplanetary gear 72g, and a fourth carrier 74g rotatably supporting thefourth planetary gear 72g and integrally coupled to the third carrier64, as well as to the output shaft 4. A fourth brake 34g is installedbetween the fourth ring gear 73g and the casing 30 such that when brake34g is actuated, the fourth ring gear 73g is locked relative to casing30.

The radial ratios within the speed ranges within this embodiment are: I₁= 0.280, I₂ = 0.520, I₃ = 0.360 and I₄ = 0.280, and tabulated below arethe gear ratios within the individual speed ranges, five forward speedranges and three reverse speed ranges, in connection with the operationsof clutches 21 and 22 and brakes 31, 32, 33 and 34g:

    ______________________________________                                        Speed Ranges                                                                             21     22     31  32  33  34g  Gear Ratios                         ______________________________________                                        first speed                                                                              o                         o    l : 4.67                            second speed                                                                             o                     o        1 : 3.78                            third speed                                                                              o                 o            1 : 2.43                            fourth speed                                                                             o             o                1 : 1.52                            fifth speed                                                                              o      o                       1 : 1.00                            reverse 1st speed o                  o    1 : -5.87                           reverse 2nd speed o              o        1 : -1.34                           reverse 3rd speed o          o            1 : -1.74                           ______________________________________                                    

Table 8 shows the relationship between the number of revolutions and thetangential force of each of the elements of the planetary gear setswithin each speed range.

Reference now being made to FIG. 9, there is schematically shown a ninthembodiment of the present invention, which is also similar to the firstembodiment, the ninth embodiment being further provided with a hollowthird intermediate shaft 6g coaxially disposed upon the output shaft 4,and a fourth sun gear 71h, of a fourth planetary gear set, generallyindicated by the reference character 70h, of the single pinion type,being fastened upon the third intermediate shaft 6h by spline means orthe like whereby sun gear 71h can rotate with the third intermediateshaft 6f. The fourth planetary gear set 70h includes the fourth sun gear71h, a fourth planetary gear 72h engaged with the fourth sun gear 71h, afourth ring gear 73h engaged with the fourth planetary gear 72h andintegrally coupled to the third ring gear 63, and a fourth carrier 74hrotatably supporting the fourth planetary gear 72h and coupled to thethird carrier 64. The ring gear 73h is of course locked relative tocasing 30 when the third brake 33 is actuated, and a fourth brake 34h issimilarly installed between the fourth sun gear 71h and the casing 30whereupon this brake being actuated, the fourth sun gear 71h will belocked relative to casing 30.

    TABLE 8      B X1 X2 X3 X4 A S1 C1 RG1 P1 S2 C2 RG2 P2 S3 C2 RG3 P3 S4 C4 RG4     P4        N -1.15 -0.25 0.0 0.70-1.15 0.26 1.00 3.06 1.00 0.26 0.0 -0.83     -0.47 0.0 0.26 1.21 F1 W 0.0 0.0 0.0 0.0 0.0 0.00 0.00 0.00 2.78 5.56     2.78 2.78 0.0 0.0 0.0 0.0  N -0.72 -0.00 0.20 0.56 -0.72 0.41 1.00 2.45     1.00 0.41 0.20 -0.66 -0.18 0.20 0.41 0.97 F2 W 1.11 2.23 1.11 1.11 0.60     1.20 0.60 0.60 1.11 2.23 1.11 1.11 0.0 0.0 0.0 0.0  N -0.46 0.15 0.32     0.47 -0.46 0.50 1.00 2.08 1.00 0.50 0.32 -0.56 0.0 0.32 0.50 0.82 F3 W     0.0 0.0 0.0 0.0 0.0 0.00 0.0 0.0 2.78 5.56 2.78 2.78 1.78 3.56 1.78 1.78      N 0.0 0.42 0.53 0.32 0.0 0.66 1.00 1.43 1.00 0.66 0.53 -0.380.32 0.53     0.66 0.56 F4 W 0.0 0.0 0.0 0.0 1.00 2.00 1.00 1.00 0.00 0.0 0.0 0.0 0.0     0.0 0.0 0.0  N 1.00 0.22 0.0 -0.61 1.00 -0.23 -0.87 -2.67 -0.87 -0.23     0.0 0.72 0.41 0.0 -0.23 -1.05 R1 W 0.0 0.0 0.0 0.0 1.92 3.85 1.92 1.92     5.34 10.68 5.34 5.34 0.0 0.0 0.0 0.0  N 1.00 0.00 -0.28 -0.78 1.00 -0.57     -1.39 -3.41 -1.39 -0.57 -0.28 0.92 0.24 -0.28 -0.57 -1.35 R2 W 2.14 4.28     2.14 2.14 0.77 1.54 0.77 0.77 2.14 4.28 2.14 2.14 0.0 0.0 0.0 0.0  N     1.00 -0.32 -0.69 -1.03 1.00 -1.08 -2.17 -4.52 -2.17 -1.08 -0.69 1.22 0.0     -0.69 -1.08 -1.78 R3 W 0.0 0.0 0.0 0.0 1.92 3.85 1.92 1.92 5.34 10.68     5.34 5.343.42 6.48 3.42 3.42

Concrete examples of the radial ratios within the speed ranges withinthis embodiment are: I₁ = 0.280, I₂ = 0.520, I₃ = 0.360 and I₄ = 0.562and tabulated below are the gear ratios within the individual speedranges, five forward speed ranges and two reverse speed ranges, inconnection with the operations of clutches 21 and 22 and brakes 31, 32,33 and 34h:

    ______________________________________                                        Speed Ranges                                                                             21     22     31  32  33  34h  Gear Ratios                         ______________________________________                                        first speed       o                  o    1 : 4.00                            second speed                                                                             o                     o        1 : 3.78                            third speed                                                                              o                 o            1 : 2.43                            fourth speed                                                                             o             o                1 : 1.52                            fifth speed                                                                              o      o                       1 : 1.00                            reverse 1st speed o              o                                            : -4.34                                                                       reverse 2nd speed o          o            1 : -1.74                           ______________________________________                                    

Table 9 shows the relationship between the number of revolutions and thetangential force of each of the elements of the planetary gear setswithin each speed range.

Thus, it may be seen that according to the present invention, as hasbeen described above, a speed change gear system capable of

    TABLE 9      B X1 X2 X3 X4 A S1 C1 RG1 P1 S2 C2 RG2 P2 S3 C2 RG3 P3 S4 C4 RG4     P4        N -1.28 -0.33 -0.06 0.74-1.28 0.22 1.00 3.26 1.00 0.22 -0.06     -0.88 1.00 0.22 0.0 -0.61 F1 W 0.0 0.0 0.0 0.0 0.0 0.00 0.00 0.00 0.0     0.0 0.0 0.0 3.57 7.14 3.57 3.57  N -1.15 -0.25 0.0 0.70 -1.15 0.26 1.00     3.06 1.00 0.26 0.0 -0.83 1.00 0.26 0.06 -0.57 F2 W 0.0 0.0 0.0 0.0 0.0     0.00 0.00 0.00 2.78 5.56 2.78 2.78 0.0 0.0 0.0 0.0  N -0.72 -0.00 0.20     0.56 -0.72 0.41 1.00 2.45 1.00 0.41 0.20 -0.66 1.00 0.41 0.25 -0.46 F3 W     1.11 2.23 1.11 1.11 0.60 1.20 0.60 0.60 1.11 2.23 1.11 1.11 0.00 0.0 0.0     0.0  N 0.0 0.42 0.53 0.32 0.0 0.66 1.00 1.43 1.00 0.66 0.53 -0.381.00     0.66 0.56 -0.27 F4 W 0.0 0.0 0.0 0.0 1.00 2.00 1.00 1.00 0.0 0.0 0.0 0.0     0.0 0.0 0.0 0.0  N 1.00 0.26 0.05 -0.58 1.00 -0.17 -0.78 -2.54 -0.78     -0.17 0.05 0.63 -0.73 -0.17 0.0 0.47 R1 W 0.0 0.0 0.0 0.0 1.92 3.85 1.92     1.92 0.0 0.0 0.0 0.0 6.87 13.74 6.87 6.87  N 1.00 0.22 0.0 -0.61 1.00     -0.23 -0.87 -2.67 -0.87 -0.23 0.0 0.72 -0.87 -0.23 -0.05 0.50 R2 W 0.0     0.0 0.0 0.0 1.92 3.85 1.92 1.92 5.34 10.68 5.34 5.34 0.0 0.0 0.0 0.0  N     1.00 0.00 -0.28 -0.78 1.00 -0.57 -1.39 -3.41 -1.39 -0.5 -0.28 0.92 -1.39     -0.57 -0.35 0.64 R3 W 2.14 4.28 2.14 2.14 0.77 1.54 0.77 0.77 2.14 4.28     2.14 2.140.0 0.0 0.0 0.0

changing between at least four forward speeds and one reverse speed canreadily be realized and which will no doubt contribute greatly to thedevelopment of the motor vehicle industry.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. It is to be understoodtherefore that within the scope of the appended claims, the presentinvention may be practiced otherwise than as specifically describedherein.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:
 1. A speed change gear which comprises:an inputshaft; an output shaft; first, second and third planetary gear setssuitably interposed between said input shaft and said output shaft; saidfirst planetary gear set including a first sun gear, a first planetarygear meshed with said first sun gear, a first ring gear meshed with saidfirst planetary gear, and a first carrier rotatably supporting saidfirst planetary gear; said second planetary gear set including a secondsun gear drivingly connected to said first sun gear, a second planetarygear meshed with said second sun gear, a second ring gear meshed withsaid second planetary gear, and a second carrier rotatably supportingsaid second planetary gear; said third planetary gear set including athird sun gear drivingly connected to said second ring gear, a thirdplanetary gear meshed with said third sun gear, a third ring gearengaged with said third planetary gear and drivingly connected to saidfirst ring gear, and a third carrier rotatably supporting said thirdplanetary gear and drivingly connected to said second carrier and tosaid output shaft; clutch means for selectively coupling said secondring and said third sun gear, and said first and second sun gears tosaid input shaft; and brake means actuatable for selective engagementwith said first and second sun gears, said first carrier, and said firstand third ring gears to said casing.
 2. A speed change gear inaccordance with claim 1, wherein said clutch means includes;a firstclutch for connecting said second ring gear and said third sun gear withsaid input shaft; and, a second clutch for connecting said first andsecond sun gears with said input shaft.
 3. A speed change gear inaccordance with claim 2, wherein said brake means includes:a first brakeselectively engageable with said first and second sun gears; a secondbrake selectively engageable with said first carrier; and, a third brakeselectively engageable with said first and third ring gears.
 4. A speedchange gear in accordance with claim 1, which further comprises:a fourthplanetary gear set including a fourth sun gear drivingly connected tosaid output shaft, a fourth planetary gear meshed with said fourth sungear, a fourth ring gear meshed with said fourth planetary gear anddrivingly connected to said third ring gear, and a fourth carrierrotatably supporting said fourth planetary gear; and, a fourth brakeactuatable for selective engagement with said fourth carrier.
 5. A speedchange gear in accordance with claim 4, wherein said brake meansincludes:a first brake selectively engageable with said first and secondsun gears; a second brake selectively engageable with said firstcarrier; and, a third brake selectively engageable with said first andthird ring gears.
 6. A speed change gear in accordance with claim 1,which further comprises:a fourth planetary gear set including a fourthsun gear drivingly connected to said third ring gear, a fourth planetarygear meshed with said fourth sun gear, a fourth ring gear meshed withsaid fourth planetary gear and drivingly connected to said output shaft,and a fourth carrier rotatably supporting said fourth planetary gear;and, a fourth brake actuatable for selective engagement with said fourthcarrier.
 7. A speed change gear in accordance with claim 6, wherein saidbrake means includes:a first brake selectively engageable with saidfirst and second sun gears; a second brake selectively engageable withsaid first carrier; and, a third brake selectively engageable with saidfirst and third ring gears.
 8. A speed change gear in accordance withclaim 1, which further comprises:a fourth planetary gear set including afourth sun gear drivingly connected to said third sun gear, a fourthplanetary gear meshed with said fourth sun gear, a fourth ring gearmeshed with said fourth planetary gear, and a fourth carrier rotatablysupporting said fourth planetary gear and drivingly connected to saidthird carrier and to said output shaft; and a fourth brake actuatablefor selective engagement with said fourth ring gear.
 9. A speed changegear in accordance with claim 8, wherein said brake means includes:afirst brake selectively engageable with said first and second sun gears;a second brake selectively engageable with said first carrier; and, athird brake selectively engageable with said first and third ring gears.10. A speed change gear in accordance with claim 1, which furthercomprises:a fourth planetary gear set including a fourth sun gear, afourth planetary gear meshed with said fourth sun gear, a fourth ringgear drivingly connected to said third ring gear and meshed with saidfourth planetary gear, and a fourth carrier rotatably supporting sidfourth planetary gear and drivingly connected to said third carrier;and, a fourth brake actuatable for selective engagement with said fourthsun gear.
 11. A speed change gear in accordance with claim 10, whereinsaid brake means includes:a first brake selectively engageable with saidfirst and second sun gears; a second brake selectively engageable withsaid first carrier; and, a third brake selectively engageable with saidfirst and third ring gears.